Network Admission Control for Fault-Tolerant QoS Provisioning
Michael Menth, Stefan Kopf, Joachim Charzinski
Abstract
In a connection oriented network layer, admission control (AC) is easily
combined with connection state management at each network node. However,
after a link or node failure, existing connections are dropped or
reservations must be restored on new paths, which requires high signalling
effort. In contrast, a connectionless network layer like IP does not deal
with connection or resource management at the network nodes. After a
failure, connectivity is easily restored by rerouting, affecting higher
layer connections only via some packet drops. Thus, a resource management
scheme for IP should allow rerouting to cope with failures without
affecting reservation states. A network admission control (NAC) handles
reservations only at dedicated locations, e.g. the borders of a network,
not burdening individual routers with admission decisions or reservation
states. The NAC architecture enables resilient resource reservation,
maintaining reservations even after failures and intra-domain rerouting.
In this paper, we investigate the efficiency of three different distributed
budget management schemes with single and multi-path routing. We show how
the admission decision can be designed to be tolerable against failure
scenarios by admitting only the amount of traffic that can still be carried
after a failure and the corresponding rerouting.
Keywords
Internet; Resource Management; Admission Control; Resilience;
Network Layer Resilience; Fast Rerouting; Network Admission Control